It's common knowlege by now - when it comes to memory in PC's, lower latency is better. But have you ever stopped to think of why it's better to have low latency memory? And is it really THAT much better? We'll find out after having a look at OCZ's latest 4GB DDR2 low-latency memory kit.

First, we should look at exactly what latencies we're talking about, and what each means. When shopping for memory or looking at PC specs, you might see some numbers like "4-4-3-15". Those refer to the rated latency of that memory's TCAS (sometimes written as CL), TRCD, TRP, and TRAS respectively.

CL - CAS Latency: The time it takes between a command having been sent to the memory and when it begins to reply to it. It is the time it takes between the processor asking for some data from the memory and it returning it.

TRCD - RAS to CAS Delay: The number of clock cycles performed between activating the Row Access Strobe and the Column Access Strobe. This parameter relates to the time it takes to access stored data.

TRP - RAS Precharge: The amount of time between the 'precharge' command and the 'active' command. The 'precharge' command closes memory that was accessed and the 'active' command signifies that a new read/write cycle can begin.

TRP - Active to Precharge Delay: The total time that will elapse between an active state and precharge state. This is the sum of the previous timings: CL + TRCD + TRP.

For a full explanation of what all this means, I am just going to refer you to Wikipedia. All you need to really know for the purpose of this review is "Lower is Better". But how much? Let's find out.

OCZ ReaperX HPC Enhanced Bandwidth PC2-6400

Talk about a mouthful! What does all that mean? OCZ's Reaper line is an original part of their Enthusiast series of memory kits. In other words, it's for people who want to tweak their systems to get the very last bit of performance out of them. ReaperX is the latest model, which features the stunning "HPC" or "HeatPipe Conduits" which are in direct contact with the surface of the memory chips.

Now you know, I am not a huge proponent of memory cooling. In my experience, memory meets the end of its performance potential long before heat ever becomes an issue. But in this case, you will at least know that heat is very unlikely to be a factor in your overclocking endeavors. Keep in mind however, that the bulky fins will make it so that these modules can NOT be installed in DIMM slots that are directly next to each other. So if your motherboard has banks that go 1-1-2-2 as opposed to 1-2-1-2, then you will have to look elsewhere if you want to run them in dual channel mode.

These modules are rated at a very nice 4-4-3-15 at PC2-6400 (aka DDR2-800) at 2.1 volts. Keep in mind that JEDEC SPD can not set voltages, so you will need to set these timings manually once you install them (don't try to run them at 4-4-3-15 with standard 1.8 voltage!). If you install them on a motherboard supporting Nvidia EPP (Enhanced Performance Profile), then you will not need to worry about setting them up.

As always, ReaperX is supported by OCZ's awesome lifetime warranty, at voltages up to 2.2v. I have actually used OCZ's tech support in the past, and it is an absolute breeze to get modules replaced.